The present invention relates to medical carbon dioxide in the exhaled breath of a patient (known as capnography). More particularly, the present invention relates to water traps used with such devices.
The measurement of a patient's carbon dioxide level is an important parameter in the diagnosis of a patient's pulmonary function. Capnography is done on a continuous basis and the values of carbon dioxide level are displayed as a curve on a CRT.
Measurement of carbon dioxide gas level is done by aspirating a continuous stream of gas from the patient's exhalation line and feeding it into an infra red sensor. The flow rate of the sample stream is usually 200 ml/min or less. In order to minimize dampening of the signal, the internal volume of the sampling line is kept as small as possible (about 2 ml.). The inside diameter of the sampling line is often 1 mm (0.40 inches) or smaller.
The exhaled gases leave the patient at 99.degree. Fahrenheit (F) and virtually 100 per cent relative humidity. The gas cools in the sampling line (the line is at room temperature usually around 70.degree.) and moisture condenses. It is important to remove this moisture from the line and collect it in a container for easy disposal.